Static random access memory (SRAM) is a type of semiconductor memory which stores data in the form of bits. SRAM includes cells which are disposed in an array. The SRAM cells include transistors coupled to bit lines and word lines. The bit lines and word lines are used to read data from and write data to the memory cell.
However, with the increasing down-scaling of integrated circuits, the operation voltages of the integrated circuits are reduced, along with the operation voltages of memories. Accordingly, read and write margins of the SRAM cells, which are measures of how reliably the data of the SRAM cells can be read from and written into, are reduced. The reduced read and write margins may cause errors in the respective read and write operations.